If A2 = 1, A3 = 3, then S4 = () A. 12B. 10C. 8D. 6

From the properties of arithmetic sequence, we can get: a1 + A4 = A2 + a3, ∵ A2 = 1, A3 = 3, ∵ S4 = 2 (1 + 3) = 8, so we choose C

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